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<p>A1.1</p>
<div style="background:red;">block</div>
<div style="background:blue; position:absolute;">postion:fixed block</div>
<span style="background:green; margin-top:30px; display:block; height:16px;">haslayout block and set margin-top is 30px</span>

<p>A1.2</p>
<div style="background:red;">block</div>
<div style="background:blue; position:absolute;">postion:fixed block</div>
<span style="background:green; margin-top:-10px; display:block; height:16px;">haslayout block and set margin-top is -10px</span>

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